Evaluation Of Fan-Out Wafer Level Package Using 200 Degrees C Curable Positive-Tone Photodefinable Polybenzoxazoles

Polyimides (PI) and polybenzoxazoles (PBO) have good heat resistance, mechanical properties and electrical insulation. Therefore, they have been widely used as buffer coating and interlayer dielectrics with protection property for electric applications. Recently, fan-out wafer level package (FOWLP) has been attracting attention, because it has advantages of multi-pin, thinner and interposer-free. In this application, it is preferable that the curing temperature of PI and PBO is less than 300 degrees C for reducing the thermal damage of semiconductor devices and packaging materials. To meet the requirement of lower curing temperature, HD MicroSystems has developed new PBO named HD-8940 designed to satisfy 200 degrees C curing process. In this study, we evaluated reliabilities of HD-8940 in FOWLP, assembling two types of test element grope (TEG). We also simulated thermal stress during reliability test by finite element method. Finally, we confirmed the applicability of HD-8940 to FOWLP.